Shortly after leaving Downing Street Mr Crabb - who had been widely tipped to replace Clwyd West MP David Jones - paid tribute to his predecessor.

He tweeted: "I will build on the excellent work of David Jones. He achieved so much during his time as Welsh secretary & leaves a strong legacy to Wales."

In further tweets, he said: "Wales deserves the best and I look forward to providing a strong voice for Wales around the Cabinet table."

He said it was a "huge privilege" to join the cabinet.

Mr Crabb added: "This Gov is ambitious for Wales, working to ensure Wales at front of the economic recovery".

Entering Gwydyr House, the Whitehall headquarters of the Wales Office, Mr Crabb said he was "looking forward to getting on with the job right now".

David Jones was seen by Labour ministers in Cardiff as someone instinctively hostile to devolution, and during First Minister's Questions Carwyn Jones said he now hoped for a "new approach and a new attitude" from the Wales Office.

Stephen Crabb met David Cameron at Downing Street on Tuesday

"I do have to say that I know that my colleagues have dealt with the new secretary of state in the past and have found him to be pragmatic and reasonable, if I can put it that way, remembering of course the obvious political difficulties and differences that are there..."

Analysis

Shadow Welsh Secretary Owen Smith urged Mr Crabb to "break free" from what he called the "ceaseless negativity" of his predecessors' attitude to Wales and the Welsh government.

The new secretary of state should "go into the new job with the aim of standing up for our nation, rather than indulging in politicised attacks on Wales, with the aim of winning votes in England", said Mr Smith.

Raised by a single parent in a council house, Stephen Crabb was first elected as Preseli Pembrokeshire MP in 2005 and re-elected in 2010. He previously a government whip and David Jones's deputy at the Wales Office.

Mr Crabb grew up in Haverfordwest and attended the town's Tasker Milward School.

Stephen Crabb entering the Wales Office as secretary of state for the first time

Carmarthen West and South Pembrokeshire MP Simon Hart MP said: "From my point of view as a Pembrokeshire colleague I think it will put a bit of an important spotlight on our part of south west Wales.

"All the years I've known Stephen, he's got a very shrewd brain. He understands business, he understands politics, he understands Wales and I think he will bring just a nice refreshing and different approach to the way politics is seen in Wales."

Mr Jones had succeeded his former Wales Office boss, Cheryl Gillan, in September 2012, and was the 16th secretary of state and the first to have been an AM, having sat in the Welsh assembly from 2002 to 2003.

Former Cardiff barrister Robert Buckland, MP for Swindon, has been made Solicitor General in the reshuffle.